Conventionally, by way of example, in the manufacturing field of a semiconductor device, there has been used a plasma etching apparatus for performing a predetermined plasma process such as an etching process onto a semiconductor wafer or a glass substrate for a liquid crystal display.
In the plasma etching apparatus, various silicon components have been used for performing a process onto a semiconductor wafer made of silicon or various silicon films. By way of example, conventionally, in the plasma etching apparatus, there has been used a silicon focus ring as a focus ring installed to surround a semiconductor wafer mounted on a mounting table. Further, as an electrode plate of a facing electrode installed to face the mounting table, there has been used a silicon electrode plate.
In the plasma etching apparatus, when a silicon component such as a silicon focus ring is exposed to the plasma, it is gradually eroded and degraded and its shape becomes changed. For this reason, reproducibility of a process becomes worse and if it is continuously used, the process quality would be deviated from an expected management value. Therefore, when the silicon component is eroded and degraded to some extent, it is regarded as an unusable component and discarded as industrial wastes. However, such a silicon component for the plasma etching apparatus is high-priced, which causes an increase in cost of consumables (COC) required for running the plasma etching apparatus.
As a countermeasure to this, there has been suggested a method in which a first ring and a second ring obtained by machining used silicon focus rings are combined and the combined silicon focus ring having a shape compatibility with a non-used silicon focus ring is recycled (see, for example, Patent Document 1). However, the method of combining rings obtained by a machining process is limited to a method of combining the machined rings having the same electric characteristic and the same shape as the non-used silicon focus ring, and, thus, a recyclable component is very restricted.
By way of example, in the manufacturing field of a solar cell, there has been suggested a recycling method that performs: a process for removing an anti-reflection film and a rear surface silver electrode film from a silicon wafer including a defective solar cell by using a hydrofluoric acid; a process for removing an aluminum electrode layer by using a hydrochloric acid; and a process for removing an impurity layer by using a mixed liquid of nitric acid and hydrofluoric acid or a sodium hydroxide in order to recover the silicon wafer including the defective solar cell to a silicon wafer capable of forming a silicon solar cell again (see, for example, Patent Document 2). However, the method of recycling the silicon wafer including the defective solar cell cannot be applied to a method of recycling various used silicon components for a plasma etching apparatus.    Patent Document 1: Japanese Patent Laid-open Publication No. 2004-79983    Patent Document 2: Japanese Patent Laid-open Publication No. 2005-166814
As described above, in a plasma etching apparatus, the silicon component for the plasma etching apparatus is a cause of an increase in cost of consumables. Further, conventionally, there has been no effective way of recycling various used silicon components for a plasma etching apparatus, which causes an increase in an amount of industrial wastes.
The present disclosure has been conceived in view of the foregoing conventional circumstances and provides a method of recycling a silicon component for a plasma etching apparatus and a silicon component for a plasma etching apparatus capable of reducing cost of consumables of the plasma etching apparatus, reducing an amount of industrial wastes, and promoting effective use of resources as compared with the conventional ones.